Hi, I am not sure you want to hear what I have to say, but I was diagnosed with HER2 _positive_ (I know you were asking for negatives)  cancer when I was 32.

Before my treatments I was offered a chance to freeze some of my eggs but told that since they aren't "ripe" they are unlikely to work. I was also told that there is very big a chance that I will be able to concieve even after the treatments as I was so young. 

The aftermath is that I have ovaries of someone who's 55. Which means it's very unlikely I'll ever get pregnant. I was devastated.

However. It took me some time to realise that the best thing I could possibly do at that point of time was to take the most effective route of treatment. I am still young, I am very much enjoying my life now 4 years after my treatments finished. (Still on tamoxifen)
My sister has promised me some of her eggs to use in case I need some, and whilst it took some time to get to terms with it... Adoption is very much an option. 

I don't know how old you are... But if you have any family, at least they will appreciate it if you take the most effective treatments. 

It is your choice obviously but life is funny in the sense that you adapt to anything and find other ways to cope, deal and have purpose. 

In my opinion, it is YOU first at the moment... and anyone/anything else after. 

All the best to you <3